Detection of the effects of repeated dose combined propoxur and heavy metal exposure by measurement of certain toxicological, haematological and immune function parameters in rats

In the present study, an immunotoxicity test system, containing general tox icological (body weight gain, organ weights), haematological (WBC,RBC, Ht, mean cell volume of the RBCs, cell content of the femoral bone marrow). and immune function (PFC assay, DTH reaction) investigations, was used for det ection the effects of a 4 weeks repeated low; dose combined oral exposure o f male Wistar rats with propoxur and the heavy metals arsenic or mercury. T wo doses of the: compounds were used: a higher one (the lowest dose which r esulted in significant change of at least one parameter examined in previou s dose-effect experiments), and a lower one (the highest dose which proved to be non-effective). The applied doses were: 8.51 and 0.851 mg kg (1) of p ropoxur, 13.3 and 3.33 mg kg(-1) of NaAsO2, and 3.20 and 0.40 mg kg(-1) of HgCl2. In the combination treatment. the high dose of propoxur was combined with the low dose of arsenic or mercury. and the high doses of each heavy metals were combined with the low dose of propoxur. The main finding of thi s study was that some of the combinations significantly altered the relativ e weight of liver, adrenals and kidneys, related to both the untreated and the high dose internal control. Among the immune functions examined, only t he PFC content of the spleen showed a trend of changes in certain combinati ons versus the corresponding high dose control. According to the present re sults, combined exposure with propoxur and the heavy metals examined can mo dify the detection limit of the single compounds and-or may alter their tox ic effects. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.